*{
    margin: 0;
    padding:0;
}
body{
    background: #F2E3CE;
}
#btn_id{/*按钮*/
    outline: none;
    border:none;
    margin:20px;
    border-radius:3px;
    font-family: "Courier New";
    width:110px;
    height: 25px;
    line-height: 25px;
    color: gray;
}
#btn_id:hover{/*按钮伪选*/
    background-color: silver;
}
#border{/*全局*/
    width:900px;
    height: 700px;
    /*border:1px black solid;*/
    margin:0 auto;
    background: #F6F6F6;
    display: none;
}